Photoelectric conversion film, solid-state image sensor, and electronic device

ABSTRACT

[Object] To provide a photoelectric conversion film, a solid-state image sensor, and an electronic device which have an increased imaging characteristic. 
     [Solution] Provided is a photoelectric conversion film including:
         a subphthalocyanine derivative represented by the following General Formula (1),       

     
       
         
         
             
             
         
       
         
         
           
             where, in General Formula (1), 
             X represents any substituent selected from among the group consisting of a halogen, a hydroxy group, a thiol group, an amino group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl amine group, a substituted or unsubstituted aryl amine group, a substituted or unsubstituted alkylthio group and a substituted or unsubstituted arylthio group, 
             R 1  to R 3  each independently represent a substituted or unsubstituted ring structure, and 
             at least one of R 1  to R 3  includes at least one hetero atom in the ring structure.

TECHNICAL FIELD

The present disclosure relates to a photoelectric conversion film, asolid-state image sensor, and an electronic device.

BACKGROUND ART

In recent years, as the number of pixels in solid-state image sensorshas increased, sizes of pixels of the solid-state image sensor have beendecreasing. However, in a planar type solid-state image sensor that iswidely used, since photoelectric conversion units are two-dimensionallyarranged as pixels, when sizes of pixels are reduced, areas ofphotoelectric conversion units are also reduced. Therefore, in theplanar type solid-state image sensor, as the number of pixels increases,an aperture ratio and light collection efficiency decrease, andsensitivity decreases.

Here, in recent years, a vertical spectral type solid-state image sensorthat separates light in a light incident direction by laminatingphotoelectric conversion units using a photoelectric conversion filmformed of an organic material has been proposed.

For example, Patent Literature 1 discloses a solid-state image sensor inwhich organic photoelectric conversion films for absorbing each of bluelight, green light and red light are laminated. In the solid-state imagesensor disclosed in Patent Literature 1, a signal of each color isextracted by performing photoelectric conversion on light correspondingto that color in each of the organic photoelectric conversion films.

In addition, in Patent Literature 2, a solid-state image sensor in whichan organic photoelectric conversion film that absorbs green light and asilicon photodiode are laminated is disclosed. In the solid-state imagesensor disclosed in Patent Literature 2, first, a signal of green lightin the organic photoelectric conversion film is extracted, a differenceof a penetration depth of light in the silicon photodiode is then usedto separate colors of blue light and red light, and signals of bluelight and red light are extracted.

CITATION LIST Patent Literature

Patent Literature 1 JP 2003-234460A

Patent Literature 2 JP 2005-303266A

SUMMARY OF INVENTION Technical Problem

Here, in order to increase an imaging characteristic, it is necessaryfor a photoelectric conversion unit in a vertical spectral typesolid-state image sensor to selectively absorb respective light of aspecific wavelength range and transmit light other than an absorptionwavelength range.

In particular, it is necessary for a photoelectric conversion unitcorresponding to green light to selectively absorb green light forphotoelectric conversion and sufficiently transmit blue light of a shortwavelength side and red light of a long wavelength side. Specifically, aphotoelectric conversion film capable of selectively absorbing greenlight is necessary. By using such a photoelectric conversion film, thesolid-state image sensor can increase sensitivity of green light, bluelight, and red light, and increase the imaging characteristic.

Therefore, the present disclosure provides a novel and improvedphotoelectric conversion film capable of increasing an imagingcharacteristic of a solid-state image sensor, a solid-state image sensorincluding the photoelectric conversion film, and an electronic deviceincluding the solid-state image sensor.

Solution to Problem

According to the present disclosure, there is provided a photoelectricconversion film including:

a subphthalocyanine derivative represented by the following GeneralFormula (1),

where, in General Formula (1),

X represents any substituent selected from among the group consisting ofa halogen, a hydroxy group, a thiol group, an amino group, a substitutedor unsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted alkyl amine group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted alkylthio group and asubstituted or unsubstituted arylthio group,

R₁ to R₃ each independently represent a substituted or unsubstitutedring structure, and at least one of R₁ to R₃ includes at least onehetero atom in the ring structure.

According to the present disclosure, there is provided a solid-stateimage sensor including:

a photoelectric conversion film including a subphthalocyanine derivativerepresented by the above General Formula (1).

According to the present disclosure, there is provided an electronicdevice including:

a solid-state image sensor including a photoelectric conversion filmincluding a subphthalocyanine derivative represented by the aboveGeneral Formula (1);

an optical system configured to guide incident light to the solid-stateimage sensor; and

an arithmetic processing circuit configured to perform arithmeticprocessing of an output signal from the solid-state image sensor.

According to the present disclosure, the photoelectric conversion filmcan selectively absorb green light and sufficiently transmit blue lightand red light.

Advantageous Effects of Invention

According to the present disclosure described above, it is possible toincrease an imaging characteristic of the solid-state image sensor.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows explanatory diagrams illustrating a solid-state imagesensor (A) including a photoelectric conversion element according to anembodiment of the present disclosure and a solid-state image sensor (B)according to a comparative example.

FIG. 2 is a graph showing an optical absorption spectrum of SubPc-Cl.

FIG. 3 is a schematic diagram illustrating an exemplary photoelectricconversion element according to an embodiment of the present disclosure.

FIG. 4 is a graph showing an optical absorption spectrum of asubphthalocyanine derivative.

FIG. 5 is a graph showing changes in a current density of aphotoelectric conversion element according to Example 9 with respect toa bias voltage.

FIG. 6 shows schematic diagrams illustrating a structure of asolid-state image sensor to which a photoelectric conversion elementaccording to an embodiment of the present disclosure is applied.

FIG. 7 is a cross-sectional view illustrating a schematic structure in aunit pixel of a solid-state image sensor to which a photoelectricconversion element according to an embodiment of the present disclosureis applied.

FIG. 8 is a block diagram illustrating a configuration of an electronicdevice to which a photoelectric conversion element according to anembodiment of the present disclosure is applied.

DESCRIPTION OF EMBODIMENT(S)

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

The description will proceed in the following order.

1. Technical background of present disclosure2. Embodiment of present disclosure2.1. Photoelectric conversion film according to embodiment of presentdisclosure2.2. Photoelectric conversion element according to embodiment of presentdisclosure2.3. Example according to embodiment of present disclosure3. Application example of photoelectric conversion film of embodimentaccording to present disclosure3.1. Configuration of solid-state image sensor3.2. Configuration of electronic device

4. Conclusion 1. TECHNICAL BACKGROUND OF PRESENT DISCLOSURE

The technological background of the present disclosure will be describedwith reference to FIGS. 1 and 2. FIG. 1(A) is a schematic diagram of avertical spectral type solid-state image sensor according to anembodiment of the present disclosure. FIG. 1(B) is a schematic diagramof a planar type solid-state image sensor according to a comparativeexample.

Hereinafter, in this specification, when it is described that “light ofa certain wavelength is absorbed,” it means that about 70% or more oflight of the wavelength is absorbed. In addition, in contrast, when itis described that “light of a certain wavelength is transmitted” or“light of a certain wavelength is not absorbed,” it means that about 70%or more of light of the wavelength is transmitted and about 30% or lessof the light is absorbed.

First, a solid-state image sensor 1 according to an embodiment of thepresent disclosure will be described with reference to FIG. 1(A). Asillustrated in FIG. 1(A), the solid-state image sensor 1 according to anembodiment of the present disclosure has a configuration in which agreen photoelectric conversion element 3G configured to absorb greenlight 2G, a blue photoelectric conversion element 3B configured toabsorb blue light 2B and a red photoelectric conversion element 3Rconfigured to absorb red light 2R are laminated.

For example, the green photoelectric conversion element 3G is aphotoelectric conversion element that selectively absorbs green lighthaving a wavelength of greater than or equal to 450 nm and less than 600nm. The blue photoelectric conversion element 3B is a photoelectricconversion element that selectively absorbs blue light having awavelength of greater than or equal to 400 nm and less than 450 nm. Thered photoelectric conversion element 3R is a photoelectric conversionelement that selectively absorbs red light having a wavelength ofgreater than or equal to 600 nm.

In the solid-state image sensor 1 according to an embodiment of thepresent disclosure, the blue photoelectric conversion element 3B and thered photoelectric conversion element 3R may be photodiodes that separatecolors into the blue light 2B and the red light 2R using a difference ofa penetration depth of light with respect to the solid-state imagesensor 1. For example, the photodiodes are silicon photodiodes thatabsorb, for example, light having a wavelength equal to or less than1100 nm.

Specifically, since the red light 2R has a longer wavelength so as to beless easily scattered than the blue light 2B, the red light 2Rpenetrates to a depth separated from a surface of incidence. On theother hand, since the blue light 2B has a shorter wavelength and is moreeasily scattered than the red light 2R, the blue light 2B penetratesonly to a depth close to the surface of incidence. Accordingly, when thered photoelectric conversion element 3R is disposed at a position deepaway from the surface of incidence of the solid-state image sensor 1, itis possible to separately detect the red light 2R from the blue light2B. Accordingly, even when the silicon photodiode is used as the bluephotoelectric conversion element 3B and the red photoelectric conversionelement 3R, the blue light 2B and the red light 2R can be separatedusing a difference of a penetration depth of light and a signal of eachcolor can be extracted.

Next, a planar type solid-state image sensor according to a comparativeexample will be described with reference to FIG. 1(B). As illustrated inFIG. 1(B), a planar type solid-state image sensor 5 includes photodiodes7R, 7G, and 7B and color filters 6R, 6G, and 6B formed on thephotodiodes 7R, 7G, and 7B.

The color filters 6R, 6G, and 6B are films that selectively transmitonly light of a specific wavelength range. For example, the color filter6R selectively transmits the red light 2R having a wavelength of greaterthan or equal to 600 nm, the color filter 6G selectively transmits thegreen light 2G having a wavelength of greater than or equal to 450 nmand less than 600 nm, and the color filter 6B selectively transmits theblue light 2B having a wavelength of greater than or equal to 400 nm andless than 450 nm.

In addition, the photodiodes 7R, 7G, and 7B are photodetection elementsconfigured to absorb light of a wide wavelength range. For example, thephotodiodes 7R, 7G, and 7B may be silicon photodiodes configured toabsorb light having a wavelength of equal to or less than 1100 nm.

Here, in the solid-state image sensor 5 shown in FIG. 1(B), since thephotodiodes 7R, 7G, and 7B absorb light of a wide wavelength range, itis difficult to perform color separation with only the photodiodes 7R,7G, and 7B. Therefore, in the solid-state image sensor 5, only lightcorresponding to each color is selectively transmitted by the colorfilters 6R, 6G, and 6B, and thus color separation is performed. Sinceonly the red light 2R, the green light 2G, and the blue light 2Bcorresponding to each color are incident on the photodiodes 7R, 7G, and7B due to the color filters 6R, 6G, and 6B, the photodiodes 7R, 7G, and7B can extract a signal of each color.

However, in the solid-state image sensor 5 shown in FIG. 1(B), lightother than light incident on the photodiodes 7R, 7G, and 7B is absorbedby the color filters 6R, 6G, and 6B. Specifically, on the photodiode 7R,only the red light 2R is incident, and the green light 2G and the bluelight 2B are absorbed by the color filter 6R. In addition, on thephotodiode 7G, only the green light 2G is incident, and the red light 2Rand the blue light 2B are absorbed by the color filter 6G. On thephotodiode 7B, only the blue light 2B is incident, and the red light 2Rand the green light 2G are absorbed by the color filter 6B.

Therefore, the photodiodes 7R, 7G, and 7B may substantially use only ⅓of incident light for photoelectric conversion. Accordingly, in thesolid-state image sensor 5 shown in FIG. 1(B), it was difficult toincrease detection sensitivity of each color.

On the other hand, in the solid-state image sensor 1 according to anembodiment of the present disclosure, the photoelectric conversionelement can selectively absorb light of a specific wavelength rangecorresponding to red, green, or blue. Therefore, in the solid-stateimage sensor 1 according to an embodiment of the present disclosure,since a color filter for performing color separation of light incidenton the photoelectric conversion element is unnecessary, it is possibleto use all incident light for photoelectric conversion. Accordingly,since the solid-state image sensor 1 according to an embodiment of thepresent disclosure can increase light that can be used for photoelectricconversion to about three times that of the solid-state image sensor 5according to a comparative example, it is possible to further increasedetection sensitivity of each color.

In the solid-state image sensor 1 according to an embodiment of thepresent disclosure, it is necessary for the photoelectric conversionelements 3G, 3B, and 3R to selectively absorb light of a specificwavelength range corresponding to red, green, or blue and transmit lighthaving a wavelength other than an absorption wavelength range.

In particular, in order to increase color separation in the bluephotoelectric conversion element 3B and the red photoelectric conversionelement 3R that are arranged below the green photoelectric conversionelement 3C it is necessary for the green photoelectric conversionelement 3G to sufficiently absorb green light and sufficiently transmitblue light and red light. Specifically, it is necessary for the greenphotoelectric conversion element 3G to have an absorption spectrum inwhich a sharp peak is represented in a wavelength range of 450 nm to 600nm.

For example, subphthalocyanine chloride (SubPc-Cl) represented by thefollowing structural formula is proposed as a green light absorbingmaterial in the green photoelectric conversion element 3G.

Here, a light absorption characteristic of SubPc-Cl is shown in FIG. 2.FIG. 2 is a graph showing an optical absorption spectrum of SubPc-Clthat is measured by a visible-ultraviolet spectrophotometer. The opticalabsorption spectrum of SubPc-Cl shown in FIG. 2 was measured using asample obtained by depositing SubPc-Cl at 50 nm on a quartz substrate,and normalized such that an absorbance at a maximum absorptionwavelength is 90%.

As shown in the result of FIG. 2, it can be understood that SubPc-Cl hasa light absorption characteristic that a peak is generally representedon a long wavelength side, and strongly absorbs light of a longerwavelength range than green light. Specifically, it can be understoodthat SubPc-Cl has a maximum absorption wavelength in the vicinity of awavelength of 600 nm and strongly absorbs light having a wavelength ofgreater than or equal to 600 nm. Therefore, when SubPc-Cl is used toform the green photoelectric conversion element 3G, since the greenphotoelectric conversion element 3G also absorbs light having awavelength corresponding to red light, sensitivity of red light islikely to decrease in the lower red photoelectric conversion element 3R.

Therefore, it is necessary to provide a subphthalocyanine derivativeappropriate for the green photoelectric conversion element 3G in whichan absorption range is shown in a shorter wavelength side than SubPc-Cland absorption of light of a long wavelength range is reduced.

In view of the above circumstances, the inventors of the presentdisclosure intensively studied a photoelectric conversion filmappropriate for the green photoelectric conversion element 3G, andcompleted the technology according to the present disclosure.Hereinafter, a photoelectric conversion film appropriate for the greenphotoelectric conversion element 3G of such a solid-state image sensorwill be described.

2. EMBODIMENT OF PRESENT DISCLOSURE 2.1. Photoelectric Conversion FilmAccording to Embodiment of Present Disclosure

A photoelectric conversion film according to an embodiment of thepresent disclosure is a photoelectric conversion film including asubphthalocyanine derivative represented by the following GeneralFormula (1).

In General Formula (1),

X represents any substituent selected from among the group consisting ofa halogen, a hydroxy group, a thiol group, an amino group, a substitutedor unsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted alkyl amine group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted alkylthio group and asubstituted or unsubstituted arylthio group,

R₁ to R₃ each independently represent a substituted or unsubstitutedring structure, and

at least one of R₁ to R₃ includes at least one hetero atom in the ringstructure.

In General Formula (1), one of bonds between a boron atom at the centerand nitrogen atoms is a coordinate bond.

As will be demonstrated in examples to be described, thesubphthalocyanine derivative represented by General Formula (1) includesat least one hetero atom in a ring structure of R₁ to R₃, and thus canhave a light absorption characteristic appropriate as a photoelectricconversion film that absorbs green light. Specifically, thesubphthalocyanine derivative represented by General Formula (1) has alight absorption characteristic that absorption of light of a longwavelength range can be reduced and light of a green light range (forexample, a wavelength of greater than or equal to 450 nm and less than600) can be selectively absorbed.

In addition, in General Formula (1), at least one of R₁ to R₃ preferablyhas a ring structure including a substituent. Specifically, when atleast one of R₁ to R₃ has a ring structure including a substituent, thesubphthalocyanine derivative represented by General Formula (1) can besynthesized at a higher yield in a synthesis method to be described. Inparticular, in a ring structure in which at least one of R₁ to R₃ issubstituted with an electron withdrawing group, since thesubphthalocyanine derivative represented by General Formula (1) can besynthesized at an even higher yield, it is preferable. For example, inGeneral Formula (1), at least one of R₁ to R₃ may have a ring structureincluding a halogen as a substituent.

Here, in General Formula (1), R₁ to R₃ may have a ring structure inwhich some hydrogen atoms are substituted with substituents or may havea ring structure in which all hydrogen atoms are substituted withsubstituents. In addition, the substituent may be substituted in a ringstructure of R₁ to R₃ such that the subphthalocyanine derivativerepresented by General Formula (1) has a symmetric property or may besubstituted in a ring structure of R₁ to R₃ such that thesubphthalocyanine derivative represented by General Formula (1) does nothave a symmetric property.

In addition, in General Formula (1), R₁ to R₃ preferably have a ringstructure including a π-conjugated system structure. When R₁ to R₃ havea ring structure including a π-conjugated system structure, thesubphthalocyanine derivative represented by General Formula (1) can havean absorption spectrum appropriate for absorbing green light having awavelength of greater than or equal to 450 nm and less than 600 nm. Onthe other hand, when at least one of R₁ to R₃ has a ring structurewithout a π-conjugated system structure, in the subphthalocyaninederivative represented by General Formula (1), a length of a conjugatedsystem of all molecules is shortened, and an absorption rangesignificantly moves to a short wavelength side. Therefore, thesubphthalocyanine derivative represented by General Formula (1) is notpreferable because absorption of blue light whose wavelength range isshorter than green light increases.

In addition, in General Formula (1), R₁ to R₃ may have a ring structureincluding any number of ring constituent atoms. Further, R₁ to R₃ mayhave a single ring structure or a fused ring structure. However,preferably, R₁ to R₃ have a ring structure including 3 or more and 8 orfewer ring constituent atoms, and more preferably, a ring structureincluding 6 ring constituent atoms. For example, when the number of ringconstituent atoms is less than 6, it is not preferable becausedistortion is likely to occur in the ring structure and thesubphthalocyanine derivative represented by General Formula (1) isdestabilized. In addition, when the number of ring constituent atoms isgreater than 6, it is not preferable because a molecular weight of thesubphthalocyanine derivative represented by General Formula (1)increases and handling is difficult.

Further, hetero atoms included in the ring structure of R₁ to R₃ arepreferably nitrogen atoms. When the nitrogen atoms are included in thering structure of R₁ to R₃, since an absorption range moves to a shortwavelength side and absorption of light of a long wavelength range isreduced, the subphthalocyanine derivative represented by General Formula(1) can be appropriately used for a photoelectric conversion film thatabsorbs green light.

Hetero atoms of R₁ to R₃ to be included in the ring structure may beincluded in the ring structure of R₁ to R₃ such that thesubphthalocyanine derivative represented by General Formula (1) has asymmetric property or may be included in the ring structure of R₁ to R₃such that the subphthalocyanine derivative represented by GeneralFormula (1) does not have a symmetric property.

Here, specific examples of the ring structure of the subphthalocyaninederivative represented by General Formula (1) are represented by thefollowing Structural Examples (1) to (17). The subphthalocyaninederivative included in the photoelectric conversion film according to anembodiment of the present disclosure is a compound having a ringstructure represented by the following Structural Examples (1) to (17).However, the ring structure of the subphthalocyanine derivativeaccording to an embodiment of the present disclosure is not limited tothe following Structural Examples (1) to (17).

In Structural Examples (1) to (17), X represents any substituentselected from among the group consisting of a halogen, a hydroxy group,a thiol group, an amino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkyl aminegroup, a substituted or unsubstituted aryl amine group, a substituted orunsubstituted alkylthio group, and a substituted or unsubstitutedarylthio group.

In addition, specific compound examples of the subphthalocyaninederivative represented by General Formula (1) are represented by thefollowing General Formulae (2) to (7). However, the subphthalocyaninederivative according to an embodiment of the present disclosure is notlimited to the compound examples represented by the following GeneralFormulae (2) to (7).

Here, in General Formulae (2) to (7), X represents any substituentselected from among the group consisting of a halogen, a hydroxy group,a thiol group, an amino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkyl aminegroup, a substituted or unsubstituted aryl amine group, a substituted orunsubstituted alkylthio group, and a substituted or unsubstitutedarylthio group.

In General Formulae (1) to (7) and Structural Examples (1) to (17), X isnot limited to the above-described substituents, but may be anysubstituent that can be bonded to a boron (B) atom. However, X ispreferably a halogen. When X is a halogen, since thermal stability ofthe subphthalocyanine derivative represented by General Formula (1)increases, it is possible to increase stability of the photoelectricconversion film.

The photoelectric conversion film including the subphthalocyaninederivative represented by General Formula (1) described above may beformed as a bulk hetero mixed film including the subphthalocyaninederivative represented by General Formula (1) as an n type photoelectricconversion material.

The bulk hetero mixed film is, for example, a film having amicrostructure in which one of the p type photoelectric conversionmaterial and the n type photoelectric conversion material forming amixed film is in a crystal fine particle state and the other thereof isin an amorphous state, and an amorphous layer uniformly covers a surfaceof crystal fine particles. In such a bulk hetero mixed film, since anarea of a pn junction that induces charge separation is increased by themicrostructure, it induces charge separation more efficiently andincrease photoelectric conversion efficiency. Alternatively, the bulkhetero mixed film may be a film having a microstructure in which boththe p type photoelectric conversion material and the n typephotoelectric conversion material forming a film are in a finecrystalline state and mixed.

In the photoelectric conversion film according to an embodiment of thepresent disclosure, when the subphthalocyanine derivative represented byGeneral Formula (1) is included as the n type photoelectric conversionmaterial, various compounds having a charge transporting characteristiccan be used as a compound to be included as the p type photoelectricconversion material.

Specifically, the p type photoelectric conversion material included inthe photoelectric conversion film according to an embodiment of thepresent disclosure preferably has at least one of a hole transportingcharacteristic and an electron transporting characteristic regardless ofan absorption wavelength. For example, the p type photoelectricconversion material may be a quinacridone derivative, a phthalocyaninederivative, a porphyrin derivative, a squarylium derivative, anaphthalene or perylene derivative, a cyanine derivative, a merocyaninederivative, a rhodamine derivative, a diphenylmethane ortriphenylmethane derivative, a xanthene derivative, an acridinederivative, a phenoxazine derivative, a quinoline derivative, an oxazolederivative, a thiazole derivative, an oxazine derivative, a thiazinederivative, a benzoquinone derivative, a naphthoquinone derivative, ananthraquinone derivative, an indigo or thioindigo derivative, a pyrrolederivative, a pyridine derivative, a jipirin derivative, an indolederivative, a diketopyrrolopyrrole derivative, a coumarin derivative, afluorene derivative, a fluoranthene derivative, an anthracenederivative, a pyrene derivative, a triarylamine derivative such astriphenylamine, naphthylamine or styrylamine, a carbazole derivative, aphenylenediamine derivative or a benzidine derivative, a phenanthrolinederivative, an imidazole derivative, an oxazoline derivative, athiazoline derivative, a triazole derivative, a thiadiazole derivative,an oxadiazole derivative, a thiophene derivative, a selenophenederivative, a silole derivative, a germole derivative, a stilbenederivative or a phenylene vinylene derivative, a pentacene derivative, arubrene derivative, a thienothiophene derivative, a benzodithiophenederivative, a xanthenoxanthene derivative, or a fullerene derivative. Inaddition, the p type photoelectric conversion material may be aconnecting body having the above-described substituent as a unitstructure, a monomer, a polymer, a copolymer or a block copolymer. Inparticular, quinacridone derivatives are preferable as the p typephotoelectric conversion material included in the photoelectricconversion film according to an embodiment of the present disclosure.

In addition, the photoelectric conversion film according to anembodiment of the present disclosure may be a planar heterojunction filmin which the subphthalocyanine derivative represented by General Formula(1) serving as the n type photoelectric conversion material and the ptype photoelectric conversion material are laminated to form aheterojunction. It is needless to say that the photoelectric conversionfilm according to an embodiment of the present disclosure may includethe subphthalocyanine derivative represented by General Formula (1) asthe p type photoelectric conversion material.

Further, the photoelectric conversion film according to an embodiment ofthe present disclosure may be formed as a monolayer film that includesonly the subphthalocyanine derivative represented by General Formula(1).

As described above, when the photoelectric conversion film according toan embodiment of the present disclosure includes the subphthalocyaninederivative represented by General Formula (1), it is possible to reduceabsorption of light of a long wavelength range and selectively absorbgreen light. Accordingly, the photoelectric conversion film according toan embodiment of the present disclosure is appropriate as the greenphotoelectric conversion element of the solid-state image sensor andimproves color separation of each color of light. Therefore, it ispossible to increase sensitivity of the solid-state image sensor andincrease an imaging characteristic.

2.2. Photoelectric Conversion Element According to Embodiment of PresentDisclosure

Next, a photoelectric conversion element according to an embodiment ofthe present disclosure will be described with reference to FIG. 3. FIG.3 is a schematic diagram illustrating an exemplary photoelectricconversion element according to an embodiment of the present disclosure.

As illustrated in FIG. 3, a photoelectric conversion element 100according to an embodiment of the present disclosure includes asubstrate 102, a lower electrode 104 arranged above the substrate 102, ap buffer layer 106 arranged above the lower electrode 104, aphotoelectric conversion layer 108 arranged above the p buffer layer106, an n buffer layer 110 arranged above the photoelectric conversionlayer 108, and an upper electrode 112 arranged above the n buffer layer110.

A structure of the photoelectric conversion element 100 shown in FIG. 3is only an example, and the structure of the photoelectric conversionelement 100 according to an embodiment of the present disclosure is notlimited to the structure shown in FIG. 3. For example, at least one ofthe p buffer layer 106 and the n buffer layer 110 may be omitted.

The substrate 102 is a support in which layers forming the photoelectricconversion element 100 are laminated and disposed. As the substrate 102,a substrate used in a general photoelectric conversion element may beused. For example, the substrate 102 may be various types of glasssubstrates such as a high strain point glass substrate, a soda glasssubstrate and a borosilicate glass substrate, a quartz substrate, asemiconductor substrate, and a plastic substrate such as apolymethylmethacrylate, polyvinyl alcohol, polyimide or polycarbonatesubstrate. In the photoelectric conversion element 100, when incidentlight is transmitted to an opposite side, the substrate 102 ispreferably formed of a transparent material.

The lower electrode 104 and the upper electrode 112 are formed of aconductive material. In addition, the lower electrode 104 is arrangedabove the substrate 102 and the upper electrode 112 is arranged abovethe n buffer layer 110. Specifically, at least one of the lowerelectrode 104 and the upper electrode 112 is formed of a transparentconductive material such as indium tin oxide (ITO) or indium zinc oxide(IZO). When incident light is transmitted to an opposite side in thephotoelectric conversion element 100, both the lower electrode 104 andthe upper electrode 112 are preferably formed of a transparentconductive material such as ITO.

As the transparent conductive material, tin oxide (TO), a tin oxide(SnO₂)-based material in which a dopant is added or a zinc oxide-basedmaterial in which a dopant is added to zinc oxide (ZnO) may be used. Asthe zinc oxide-based material, for example, aluminum zinc oxide (AZO) inwhich aluminum (Al) is added as a dopant, gallium zinc oxide (GZO) inwhich gallium (Ga) is added, and indium zinc oxide (IZO) in which indium(In) is added can be exemplified. In addition thereto, as thetransparent conductive material, CuI, InSbO₄, ZnMgO, CuInO₂, MgIN₂O₄,CO, ZnSnO₃ or the like may be used. Further, as the transparentconductive material, indium gallium zinc oxide (IGZO), indium galliumoxide (IGO), aluminum gallium zinc oxide (AGZO), graphene, a metallicthin film, and PEDOT may be used.

Further, a bias voltage is applied to the lower electrode 104 and theupper electrode 112. For example, the bias voltage is applied to set apolarity such that electrons move to the upper electrode 112 and holesmove to the lower electrode 104 among charges generated in thephotoelectric conversion layer 108.

In addition, it is needless to say that the bias voltage may be appliedto set a polarity such that holes move to the upper electrode 112 andelectrons move to the lower electrode 104 among charges generated in thephotoelectric conversion layer 108. In this case, in the photoelectricconversion element 100 illustrated in FIG. 3, positions of the p-bufferlayer 106 and the n-buffer layer 110 are switched.

The p buffer layer 106 is a layer that is arranged above the lowerelectrode 104 and provides a function of extracting a hole from thephotoelectric conversion layer 108 with high efficiency. Specifically,the p buffer layer 106 includes the p type photoelectric conversionmaterial having at least one of a hole transporting characteristic andan electron transporting characteristic. As the p type photoelectricconversion material, for example, a quinacridone derivative, aphthalocyanine derivative, a porphyrin derivative, a squaryliumderivative, a naphthalene or perylene derivative, a cyanine derivative,a merocyanine derivative, a rhodamine derivative, a diphenylmethane ortriphenylmethane derivative, a xanthene derivative, an acridinederivative, a phenoxazine derivative, a quinoline derivative, an oxazolederivative, a thiazole derivative, an oxazine derivative, a thiazinederivative, a benzoquinone derivative, a naphthoquinone derivative, ananthraquinone derivative, an indigo or thioindigo derivative, a pyrrolederivative, a pyridine derivative, a jipirin derivative, an indolederivative, a diketopyrrolopyrrole derivative, a coumarin derivative, afluorene derivative, a fluoranthene derivative, an anthracenederivative, a pyrene derivative, a triarylamine derivative such astriphenylamine, naphthylamine or styrylamine, a carbazole derivative, aphenylenediamine derivative or a benzidine derivative, a phenanthrolinederivative, an imidazole derivative, an oxazoline derivative, athiazoline derivative, a triazole derivative, a thiadiazole derivative,an oxadiazole derivative, a thiophene derivative, a selenophenederivative, a silole derivative, a germole derivative, a stilbenederivative or a phenylene vinylene derivative, a pentacene derivative, arubrene derivative, a thienothiophene derivative, a benzodithiophenederivative, a xanthenoxanthene derivative, or a fullerene derivative canbe exemplified. In addition, the p type photoelectric conversionmaterial may be a connecting body having the above-described substituentas a unit structure, a monomer, a polymer, a copolymer or a blockcopolymer. A wavelength band of light that the p type photoelectricconversion material absorbs is not particularly limited and may be anywavelength band.

More specifically, the p buffer layer 106 may be formed of a holetransporting material and may be formed of an arylamine, oxazole,oxadiazole, triazole, imidazole, stilbene, a polyarylalkane, porphyrin,anthracene, fluorenone, hydrazine or derivatives thereof. For example,the p buffer layer 106 may be formed ofN,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine(TPD),4,4′-bis[N-(naphthyl)-N-phenylamino] biphenyl(α-NPD),4,4′,4″-tris(N-(3-methylphenyl)N-phenylamino)triphenylamine(m-MTDATA),tetraphenylporphyrin copper, phthalocyanine, or copper phthalocyanine.

The photoelectric conversion layer 108 is a layer that is arranged abovethe p buffer layer 106 and provides a function of selectively absorbinggreen light (for example, light having a wavelength of greater than orequal to 450 nm and less than 600 nm) and photoelectrically convertingthe absorbed light. In the photoelectric conversion element according toan embodiment of the present disclosure, the photoelectric conversionlayer 108 includes the above-described subphthalocyanine derivativerepresented by General Formula (1). For example, the photoelectricconversion layer 108 may be a bulk hetero mixed film that includes thesubphthalocyanine derivative represented by General Formula (1) as the ntype photoelectric conversion material and a quinacridone derivative asthe p type photoelectric conversion material.

The photoelectric conversion layer 108 may be formed as a single layerin which the n type photoelectric conversion material and the p typephotoelectric conversion material are mixed at a single ratio. Inaddition, the photoelectric conversion layer 108 may be formed of aplurality of layers in which the mixing ratio of the n typephotoelectric conversion material and the p type photoelectricconversion material is changed in a lamination direction. For example,the photoelectric conversion layer 108 may have a multilayer structurein which a p layer formed of the p type photoelectric conversionmaterial from the p buffer layer 106 side, an i layer in which the ntype photoelectric conversion material and the p type photoelectricconversion material are mixed, and an n layer formed of the n typephotoelectric conversion material are laminated.

In the photoelectric conversion element according to an embodiment ofthe present disclosure, as long as the subphthalocyanine derivativerepresented by General Formula (1) is included, the photoelectricconversion layer 108 is not limited to the bulk hetero mixed film, andmay be formed of a monolayer film, a planar heterojunction film, or thelike.

The n buffer layer 110 is a layer that is arranged above thephotoelectric conversion layer 108 and provides a function of extractingelectrons from the photoelectric conversion layer 108 with highefficiency. Specifically, the n buffer layer 110 is formed of anelectron transporting material, and may be formed of, for example,fullerenes, carbon nanotubes, oxadiazole, a triazole compound,anthraquinodimethane, diphenyl quinone, a distyrylarylene, a silolecompound or derivatives thereof. Specifically, the n buffer layer 110may be formed of 1,3-bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)phenylene(OXD-7), bathocuproine, bathophenanthroline, ortris(8-hydroxyquinolinate)aluminum (Alq3).

In addition, in the structure of the photoelectric conversion element100 illustrated in FIG. 3, materials forming layers other than thephotoelectric conversion layer 108 are not specifically limited, but aknown material for the photoelectric conversion element may also beused.

Here, each of the layers in the photoelectric conversion element 100according to an embodiment of the present disclosure described above maybe formed by an appropriate film formation method that is selectedaccording to a material such as a vacuum deposition, a sputtering, andvarious coating methods.

For example, in each of the layers forming the photoelectric conversionelement 100 according to an embodiment of the present disclosure, thelower electrode 104 and the upper electrode 112 may be formed by adeposition method including an electron beam deposition method, a hotfilament deposition method and a vacuum deposition method, a sputteringmethod, a combination of a chemical vapor deposition method (CVDmethod), an ion plating method and an etching method, various types ofprinting methods such as a screen printing method, an ink jet printingmethod and a metal mask printing method, or a plating method (anelectroplating method and an electroless plating method), and the like.

In addition, in each of the layers forming the photoelectric conversionelement 100 according to an embodiment of the present disclosure, eachlayer such as the p-buffer layer 106, the photoelectric conversion layer108 and the n-buffer layer 110 may be formed by, for example, thedeposition method such as the vacuum deposition method, the printingmethod such as the screen printing method and the ink jet printingmethod, a laser transfer method and the coating method such as a spincoating method.

An exemplary configuration of the photoelectric conversion element 100according to an embodiment of the present disclosure has been describedabove.

2.3. Example According to Embodiment of Present Disclosure

Hereinafter, the subphthalocyanine derivative, the photoelectricconversion film and the photoelectric conversion element according to anembodiment of the present disclosure will be described in detail withreference to examples and comparative examples. However, the followingexamples are only examples and the photoelectric conversion film and thephotoelectric conversion element according to an embodiment of thepresent disclosure are not limited to the following examples.

[Simulation Analysis]

First, spectral characteristics of the subphthalocyanine derivativeaccording to an embodiment of the present disclosure were evaluated bysimulation analysis. Specifically, the simulation analysis was performedon the subphthalocyanine derivatives represented by the followingstructural formula and a maximum absorption wavelength λ_(max) wascalculated. For comparison, the simulation analysis was performed onsubphthalocyanine derivatives (SubPc-Cl, SubPc-F) according to acomparative example, and a maximum absorption wavelength λ_(max) wascalculated.

In the simulation analysis, molecular orbital calculation using densityfunctional theory (DFT) was used, Gaussian03 was used as a calculationprogram, and “6-311++G” was used as a basis function at the functionallevel of “B3LYP.”

Specifically, first, structure optimization calculation was performed oneach of the subphthalocyanine derivatives by a self-consistent field(SCF) and an energy level of each molecular orbital was computed. Next,time-dependent density functional theory (TD-DFT) was applied, anultraviolet-visible absorption (UV-VIS) spectrum was calculated, and amaximum absorption wavelength λ_(max) was computed.

The maximum absorption wavelengths λ_(max) of each of thesubphthalocyanine derivatives computed by the simulation analysis areshown in the following Table 1. Since the maximum absorption wavelengthsλ_(max) of the subphthalocyanine derivatives shown in Table 1 aresimulation analysis results in a single molecule, absolute valuesthereof do not match actual measurement values of absorption spectrumsthat were actually measured in a solution which will be described.However, as can be understood from actual measurement values ofabsorption spectrums in a solution which will be described, tendenciesof the following simulation analysis results and the actual measurementresults match.

TABLE 1 λ_(max) [nm] Example 1 SubNPc-F 456.8 Example 2 pyri-SubNPc-F463.8 Example 3 isopyri-SubNPc-F 466.7 Example 4 imida-SubNPc-F 431.1Example 5 6Cl-SubNPc-Cl 464.3 Example 6 6Me-SubNPc-Cl 459.4 Example 76F-SubNPc-Cl 458.3 Example 8 6F-SubNPc-F 460.6 Comparative SubPc-Cl496.0 Example 1 Comparative SubPc-F 499.5 Example 2

As shown in the results in Table 1, it can be understood thatsubphthalocyanine derivatives according to Examples 1 to 8 have ashorter maximum absorption wavelength λ_(max) and have more reducedabsorption of light of a long wavelength range than subphthalocyaninederivatives according to Comparative Examples 1 and 2.

Specifically, comparing Example 1 and Comparative Examples 1 and 2, itcan be understood that, regardless of a substituent that is bonded to aboron atom at the center, when a nitrogen atom serving as a hetero atomis introduced into the ring structure of R₁ to R₃ in General Formula(1), λ_(max) becomes a short wavelength. In addition, comparing Examples1 and 5 to 7, it can be understood that, even if a substituent isintroduced into the ring structure of R₁ to R₃ in General Formula (1),similarly, λ_(max) becomes a shorter wavelength. Further, comparingExamples 1 to 4, it can be understood that, regardless of the number ofring constituent atoms of the ring structure of R₁ to R₃ in GeneralFormula (1) and regardless of the number of hetero atoms included in thering structure of R₁ to R₃ and positions thereof, λ_(max) becomes ashorter wavelength.

Accordingly, it can be understood that, in the subphthalocyaninederivative according to an embodiment of the present disclosure, atleast one hetero atom is included in the ring structure of at least oneof R₁ to R₃ in General Formula (1), and thus a maximum absorptionwavelength can become a shorter wavelength.

[Synthesis of Subphthalocyanine Derivative]

Next, a method of synthesizing the subphthalocyanine derivativeaccording to an embodiment of the present disclosure will be described.The subphthalocyanine derivative according to an embodiment of thepresent disclosure can be synthesized by a generalized synthesis methodrepresented by the following Reaction Formula 1. The synthesis method tobe described is only an example, and the method of synthesizing thesubphthalocyanine derivative according to an embodiment of the presentdisclosure is not limited to the following example.

As shown in Reaction Formula 1, when 2,3-dicyanopyrazine derivatives andboron trichloride are mixed in a solvent and heated to reflux, it ispossible to synthesize the subphthalocyanine derivative according to anembodiment of the present disclosure. In Reaction Formula 1, whilesubstituents Y substituted in 2,3-dicyanopyrazine derivatives aredescribed as the same substituents, it is needless to say that thesubstituents Y in 2,3-dicyanopyrazine derivatives may be different fromeach other.

Further, a specific method of synthesizing the subphthalocyaninederivative according to an embodiment of the present disclosure will bedescribed by exemplifying specific compounds.

Synthesis of SubNPc-Cl

SubNPc-Cl represented by the following structural formula wassynthesized by the following method.

2,3-dicyanopyrazine (in Reaction Formula 1, Y═H) at 3 mmol and borontrichloride (a dichloromethane solution) at 1 mmol (1 ml) were addedinto a flask, and heated to reflux using 3 ml of 1-chloro-naphthalene ina solvent. A Dimroth cooler was connected to the mouth of the flask, anupper portion of the Dimroth cooler was additionally guided to anexhaust port of a draft by a rubber tube, and a low boiling pointcomponent was gradually evaporated. The flask had a bath temperaturethat was set to 190° C. and heated to reflux for about 16 hours.

After being heated to reflux, the mixture was left overnight, filtered,and further washed with dichloromethane. A filtrate was purified bycolumn chromatography and thus 6 mg of a red component SubNPc-Cl (yield1.3%) was obtained. When ¹H-nuclear magnetic resonance (NMR) measurementwas performed on the obtained SubNPc-Cl in a CDCl₃ solvent, it wasdetermined that a main peak was in one singlet (δ=9.240) in an aromaticregion, and a reaction product was SubNPc-Cl.

Synthesis of 6Cl-SubNPc-Cl

In addition, according to a synthesis method similar to that ofSubNPc-Cl, 6Cl-SubNPc-Cl represented by the following structural formulawas synthesized.

Synthesis of the above SubNPc-Cl was performed by a similar methodexcept that 5,6-dichloro-2,3-dicyanopyrazine (in Reaction Formula 1,Y═Cl) was used as a starting material in place of 2,3-dicyanopyrazine,and 6Cl-SubNPc-Cl was obtained. A yield of 6Cl-SubNPc-Cl was 11%.

Synthesis of 2Cl-SubNPc-Cl, 4Cl-SubNPc-Cl

In addition, for example, by a synthesis method represented by thefollowing Reaction Formula 2, it is possible to synthesizesubphthalocyanine derivatives (2Cl-SubNPc-Cl and 4Cl-SubNPc-Cl) havingdifferent ring structures of R₁ to R₃.

A mixture at 3 mmol of phthalonitrile and5,6-dichloro-2,3-dicyanopyrazine (molar ratio 1:1) and boron trichloride(a dichloromethane solution) at 1 mmol (1 ml) were added to a flask andheated to reflux using 3 ml of 1-chlorobenzene in a solvent. A Dimrothcooler was connected to the mouth of the flask, an upper portion of theDimroth cooler was additionally guided to an exhaust port of a draft bya rubber tube, and a low boiling point component was graduallyevaporated. The flask had a bath temperature that was set to 190° C. andheated to reflux for about 16 hours.

After being heated to reflux, the mixture was left overnight, filtered,and further washed with dichloromethane. A filtrate was purified bycolumn chromatography, and thus four types of derivatives (SubPc-Cl,2Cl-SubNPc-Cl, 4Cl-SubNPc-Cl, and 6Cl-SubNPc-Cl) in Reaction Formula 2were obtained. According to the above-described synthesis method, it waspossible to synthesize 2Cl-SubNPc-Cl and 4Cl-SubNPc-Cl having differentring structures of R₁ to R₃.

[Evaluation of Subphthalocyanine Derivative]

Next, spectral characteristics of SubNPc-Cl and 6Cl-SubNPc-Clsynthesized above were evaluated by a solution method. In addition, forcomparison, spectral characteristics of SubPc-Cl were evaluated by asimilar method.

Specifically, each of the subphthalocyanine derivatives was dissolved ino-xylene, and an optical absorption spectrum was acquired by avisible-ultraviolet spectrophotometer using a quartz cell. The acquiredoptical absorption spectrums of the subphthalocyanine derivatives areshown in FIG. 4. The optical absorption spectrums shown in FIG. 4 arenormalized such that an absorbance at a maximum absorption wavelength ineach of the subphthalocyanine derivatives is 1.

As seen from the results shown in FIG. 4, it can be understood thatSubNPc-Cl and 6Cl-SubNPc-Cl that are the subphthalocyanine derivativesaccording to an embodiment of the present disclosure have a shortermaximum absorption wavelength than SubPc-Cl according to a comparativeexample. In addition, it can be understood that tendencies of measuredmaximum absorption wavelengths of 6Cl-SubNPc-Cl and SubPc-Cl matchtendencies of maximum absorption wavelengths of Example 5 andComparative Example 1 of the above simulation analysis and the abovesimulation analysis is appropriate.

[Evaluation of Photoelectric Conversion Element]

In addition, 6Cl-SubNPc-Cl synthesized as above was used to manufacturea photoelectric conversion element according to an embodiment of thepresent disclosure and it was determined that the photoelectricconversion element functioned as a photoelectric conversion element.

Example 9

First, indium tin oxide (ITO) was formed into a film of 100 nm on aquartz substrate by a sputtering method, and the formed ITO thin filmwas patterned by photolithography and then etched to form a transparentlower electrode. Next, the formed transparent electrode was washedthrough UV/ozone treatment, a shadow mask was used to perform vacuumdeposition such that a film formation ratio of 6Cl-SubNPc-Cl andquinacridone became 1:1, and thus a photoelectric conversion layer wasformed.

Subsequently, aluminum (Al) was vacuum-deposited on the photoelectricconversion layer using a shadow mask and thus an upper electrode wasformed. According to the above manufacturing method, the photoelectricconversion element was manufactured.

Subsequently, a photoelectric conversion function of the manufacturedphotoelectric conversion element according to Example 9 was evaluated.Specifically, a prober connected to a semiconductor parameter analyzerwas used, a bias voltage was applied to an upper electrode and a lowerelectrode of the photoelectric conversion element according to Example1, and a current value with and without illumination through a quartzsubstrate was measured.

The evaluation result of the photoelectric conversion function of thephotoelectric conversion element according to Example 9 is shown in FIG.5. FIG. 5 is a graph showing changes in a current density of thephotoelectric conversion element according to Example 9 with respect toa bias voltage.

As seen from the results shown in FIG. 5, it can be understood that, inthe photoelectric conversion element according to Example 9, in a biasvoltage range of 0 to −3 V, a current density under illuminationincreases more than a current density with no illumination, and thephotoelectric conversion function is provided. Accordingly, it can beunderstood that the subphthalocyanine derivative according to anembodiment of the present disclosure can be appropriately used as aphotoelectric conversion material included in the photoelectricconversion film.

As can be understood from the above result, when the photoelectricconversion film according to an embodiment of the present disclosureincludes the subphthalocyanine derivative represented by General Formula(1), it is possible to reduce absorption of light of a long wavelengthrange and selectively absorb green light. Accordingly, it can beunderstood that the photoelectric conversion film according to anembodiment of the present disclosure can be appropriately used as thegreen photoelectric conversion element of the solid-state image sensorand can increase an imaging characteristic of the solid-state imagesensor.

3. APPLICATION EXAMPLE OF PHOTOELECTRIC CONVERSION ELEMENT ACCORDING TOAN EMBODIMENT OF THE PRESENT DISCLOSURE

Hereinafter, an application example of the photoelectric conversionelement including the photoelectric conversion film according to anembodiment of the present disclosure will be described with reference toFIGS. 6 to 8.

3.1. Configuration of Solid-State Image Sensor

First, a configuration of the solid-state image sensor to which thephotoelectric conversion element according to an embodiment of thepresent disclosure is applied will be described with reference to FIGS.6 and 7. FIG. 6 is a schematic diagram illustrating a structure of asolid-state image sensor to which the photoelectric conversion elementaccording to an embodiment of the present disclosure is applied.

Here, in FIG. 6, pixel areas 201, 211 and 231 are areas in which thephotoelectric conversion element including the photoelectric conversionfilm according to an embodiment of the present disclosure are disposed.In addition, control circuits 202, 212 and 242 are arithmetic processingcircuits configured to control each component of the solid-state imagesensor. Logic circuits 203, 223 and 243 are signal processing circuitsconfigured to process a signal obtained by photoelectric conversion ofthe photoelectric conversion element in the pixel area.

For example, as illustrated in FIG. 6A, in the solid-state image sensorto which the photoelectric conversion element according to an embodimentof the present disclosure is applied, the pixel area 201, the controlcircuit 202 and the logic circuit 203 may be formed in one semiconductorchip 200.

In addition, as illustrated in FIG. 6B, the solid-state image sensor towhich the photoelectric conversion element according to an embodiment ofthe present disclosure is applied may be a laminated type solid-stateimage sensor in which the pixel area 211 and the control circuit 212 areformed in a first semiconductor chip 210, and the logic circuit 223 isformed in a second semiconductor chip 220.

Further, as illustrated in FIG. 6C, the solid-state image sensor towhich the photoelectric conversion element according to an embodiment ofthe present disclosure is applied may be a laminated type solid-stateimage sensor in which the pixel area 231 is formed in a firstsemiconductor chip 230 and the control circuit 242 and the logic circuit243 are formed in a second semiconductor chip 240.

In the solid-state image sensors illustrated in FIG. 6B and FIG. 5C, thepixel area is formed in a separate semiconductor chip from thesemiconductor chip in which at least one of the control circuit and thelogic circuit is formed. Accordingly, since the solid-state imagesensors illustrated in FIG. 6B and FIG. 5C can extend the pixel areamore than the solid-state image sensor illustrated in FIG. 6A, thenumber of pixels accommodated in the pixel area is increased. Therefore,it is possible to increase a plane resolution of the solid-state imagesensors. For this reason, it is more preferable that the solid-stateimage sensor to which the photoelectric conversion element according toan embodiment of the present disclosure is applied be the laminated typesolid-state image sensor illustrated in FIG. 6B and FIG. 5C.

Subsequently, a specific structure of a solid-state image sensor towhich the photoelectric conversion element according to an embodiment ofthe present disclosure is applied will be described with reference toFIG. 7. FIG. 7 is a cross sectional view illustrating an outlinestructure of a unit pixel of a solid-state image sensor to which thephotoelectric conversion element according to an embodiment of thepresent disclosure is applied. In addition, a solid-state image sensor300 illustrated in FIG. 7 is a rear surface irradiation type solid-stateimage sensor in which light is incident from a surface opposite to asurface in which a pixel transistor and the like are formed. Inaddition, with respect to the drawing, an upper side is a lightreceiving surface, and a lower side is a circuit forming surface inwhich the pixel transistor and a peripheral circuit are formed.

As illustrated in FIG. 7, the solid-state image sensor 300 has aconfiguration in which, in a photoelectric conversion area 320, aphotoelectric conversion element including a first photodiode PD1 formedin a semiconductor substrate 330, a photoelectric conversion elementincluding a second photodiode PD2 formed in the semiconductor substrate330 and a photoelectric conversion element including an organicphotoelectric conversion film 310 formed at a rear surface side of thesemiconductor substrate 330 are laminated in a direction of incidence oflight.

The first photodiode PD1 and the second photodiode PD2 are formed in awell area 331 that is a first conductivity type (for example, a p type)semiconductor area of the semiconductor substrate 330 made of silicon.

The first photodiode PD1 includes an n type semiconductor area 332according to a second conductivity type (for example, an n type)impurity formed at a light receiving surface side of the semiconductorsubstrate 330 and an extending portion 332 a that is formed by extendinga part thereof to reach a surface side of the semiconductor substrate330. A high concentration p type semiconductor area 334 serving as acharge accumulation layer is formed on a surface of the extendingportion 332 a. In addition, the extending portion 332 a is formed as anextraction layer for extracting a signal charge accumulated in the ntype semiconductor area 332 of the first photodiode PD1 to a surfaceside of the semiconductor substrate 330.

The second photodiode PD2 includes an n type semiconductor area 336formed at a light receiving surface side of the semiconductor substrate330 and a high concentration p type semiconductor area 338 that isformed at a surface side of the semiconductor substrate 330 as a chargeaccumulation layer.

In the first photodiode PD1 and the second photodiode PD2, when the ptype semiconductor area is formed at an interface of the semiconductorsubstrate 330, it is possible to suppress the dark current generated atthe interface of the semiconductor substrate 330.

Here, the second photodiode PD2 formed in an area that is farthest fromthe light receiving surface is, for example, a red photoelectricconversion element that absorbs red light and performs photoelectricconversion. In addition, the first photodiode PD1 formed closer to thelight receiving surface side than the second photodiode PD2 is, forexample, a blue photoelectric conversion element that absorbs blue lightand performs photoelectric conversion.

The organic photoelectric conversion film 310 is formed on a rearsurface of the semiconductor substrate 330 through an antireflectionfilm 302 and an insulation film 306. In addition, the organicphotoelectric conversion film 310 is interposed between an upperelectrode 312 and a lower electrode 308 to form the photoelectricconversion element. Here, the organic photoelectric conversion film 310is, for example, an organic film that absorbs green light of awavelength of greater than or equal to 450 nm and less than 600 nm andperforms photoelectric conversion and is formed as the photoelectricconversion film according to an embodiment of the present disclosuredescribed above. In addition, the upper electrode 312 and the lowerelectrode 308 are made of, for example, a transparent conductivematerial such as indium tin oxide (ITO) or indium zinc oxide (IZO).

In addition, the lower electrode 308 is connected to a vertical transferpath 348 that is formed from the rear surface side to the surface sideof the semiconductor substrate 330 through a contact plug 304penetrating the antireflection film 302. The vertical transfer path 348is formed to have a structure in which a connecting portion 340, apotential barrier layer 342, a charge accumulation layer 344 and a ptype semiconductor area 346 are laminated from the rear surface side ofthe semiconductor substrate 330.

The connecting portion 340 includes an n type impurity area of a highimpurity concentration that is formed at the rear surface side of thesemiconductor substrate 330 and is formed for an ohmic contact with thecontact plug 304. The potential barrier layer 342 includes a p typeimpurity area of a low concentration and forms a potential barrierbetween the connecting portion 340 and the charge accumulation layer344. The charge accumulation layer 344 accumulates a signal chargetransmitted from the organic photoelectric conversion film 310 and isformed in an n type impurity area of a lower concentration than theconnecting portion 340. In addition, the p type semiconductor area 346of a high concentration is formed on a surface of the semiconductorsubstrate 330. With this p type semiconductor area 346, it is possibleto suppress the dark current generated at the interface of thesemiconductor substrate 330.

Here, at the surface side of the semiconductor substrate 330, amultilayer wiring layer 350 including wires 358 laminated in a pluralityof layers is formed through an interlayer insulating layer 351. Inaddition, in the vicinity of the surface of the semiconductor substrate330, read circuits 352, 354 and 356 corresponding to the firstphotodiode PD1, the second photodiode PD2 and the organic photoelectricconversion film 310 are formed. The read circuits 352, 354 and 356 reada signal output from each photoelectric conversion element and transmitthe signal to the logic circuit (not illustrated). Further, a supportingsubstrate 360 is formed on a surface of the multilayer wiring layer 350.

On the other hand, at a light receiving surface side of the upperelectrode 312, a light shielding film 316 is formed to shield theextending portion 332 a of the first photodiode PD1 and the verticaltransfer path 348. Here, a separate area between the light shieldingfilms 316 is the photoelectric conversion area 320. In addition, anon-chip lens 318 is formed above the light shielding film 316 through aflattening film 314.

The solid-state image sensor 300 to which the photoelectric conversionelement according to an embodiment of the present disclosure is appliedhas been described above. In addition, in the solid-state image sensor300 to which the photoelectric conversion element according to anembodiment of the present disclosure is applied, since color separationis performed on a unit pixel in a longitudinal direction, a color filterand the like are not provided.

3.2. Configuration of Electronic Device

Next, a configuration of an electronic device to which the photoelectricconversion element according to an embodiment of the present disclosureis applied will be described with reference to FIG. 8. FIG. 8 is a blockdiagram illustrating a configuration of an electronic device to whichthe photoelectric conversion element according to an embodiment of thepresent disclosure is applied.

As illustrated in FIG. 8, an electronic device 400 includes an opticalsystem 402, a solid-state image sensor 404, a digital signal processor(DSP) circuit 406, a control unit 408, an output unit 412, an input unit414, a frame memory 416, a recording unit 418 and a power supply unit420.

Here, the DSP circuit 406, the control unit 408, the output unit 412,the input unit 414, the frame memory 416, the recording unit 418 and thepower supply unit 420 are connected to each other via a bus line 410.

The optical system 402 obtains incident light from an object and formsan image on an imaging surface of the solid-state image sensor 404. Inaddition, the solid-state image sensor 404 includes the photoelectricconversion element according to an embodiment of the present disclosure,converts an intensity of incident light focused on an imaging surface bythe optical system 402 into an electrical signal in units of pixels, andoutputs the result as a pixel signal.

The DSP circuit 406 processes the pixel signal transmitted from thesolid-state image sensor 404 and outputs the result to the output unit412, the frame memory 416, the recording unit 418 and the like. Inaddition, the control unit 408 includes, for example, an arithmeticprocessing circuit, and controls operations of each of the components ofthe electronic device 400.

The output unit 412 is, for example, a panel type display device such asa liquid crystal display and an organic electroluminescent display, anddisplays a video or a still image imaged by the solid-state image sensor404. Here, the output unit 412 may also include a sound output devicesuch as a speaker and a headphone. Here, the input unit 414 is, forexample, a device for inputting a user's manipulation such as a touchpanel and a button and issues manipulation commands for variousfunctions of the electronic device 400 according to the user'smanipulation.

The frame memory 416 temporarily stores the video, the still image andthe like imaged by the solid-state image sensor 404. In addition, therecording unit 418 records the video, the still image and the likeimaged by the solid-state image sensor 404 in a removable storage mediumsuch as a magnetic disk, an optical disc, a magneto optical disc and asemiconductor memory.

The power supply unit 420 appropriately supplies various types of powerserving as operating power of the DSP circuit 406, the control unit 408,the output unit 412, the input unit 414, the frame memory 416 and therecording unit 418 to these supply targets.

The electronic device 400 to which the photoelectric conversion elementaccording to an embodiment of the present disclosure is applied has beendescribed above. The electronic device 400 to which the photoelectricconversion element according to an embodiment of the present disclosureis applied may be, for example, an imaging apparatus.

4. CONCLUSION

As described above, when the photoelectric conversion film according toan embodiment of the present disclosure includes the subphthalocyaninederivative represented by General Formula (1), it is possible to reduceabsorption of a long wavelength side and selectively absorb light of agreen light range.

In addition, since the photoelectric conversion film according to anembodiment of the present disclosure can selectively absorb green light,it can be appropriately used as the green photoelectric conversionelement of the solid-state image sensor. Accordingly, since thephotoelectric conversion film according to an embodiment of the presentdisclosure can improve color separation of each color of light, it ispossible to increase sensitivity of the solid-state image sensor andincrease an imaging characteristic. In particular, since thephotoelectric conversion film according to an embodiment of the presentdisclosure increases transparency of red light of a long wavelengthside, it is possible to increase sensitivity of red light in thesolid-state image sensor.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art based on the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A photoelectric conversion film including:

a subphthalocyanine derivative represented by the following GeneralFormula (1),

where, in General Formula (1),

X represents any substituent selected from among the group consisting ofa halogen, a hydroxy group, a thiol group, an amino group, a substitutedor unsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted alkyl amine group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted alkylthio group and asubstituted or unsubstituted arylthio group,

R₁ to R₃ each independently represent a substituted or unsubstitutedring structure, and

at least one of R₁ to R₃ includes at least one hetero atom in the ringstructure.

(2)

The photoelectric conversion film according to (1),

wherein at least one of R₁ to R₃ has a ring structure including asubstituent.

(3)

The photoelectric conversion film according to (2),

wherein the substituent of R₁ to R₃ is a halogen.

(4)

The photoelectric conversion film according to any one of (1) to (3),

wherein R₁ to R₃ have a ring structure including a π-conjugated systemstructure.

(5)

The photoelectric conversion film according to any one of (1) to (4),

wherein R₁ to R₃ have a ring structure including 3 or more and 8 orfewer ring constituent atoms.

(6)

The photoelectric conversion film according to (5),

wherein R₁ to R₃ have a ring structure including 6 ring constituentatoms.

(7)

The photoelectric conversion film according to any one of (1) to (6),

wherein a hetero atom included in the ring structure of R₁ to R₃ is anitrogen atom.

(8)

The photoelectric conversion film according to any one of (1) to (7),

wherein X is a halogen.

(9)

A solid-state image sensor including:

a photoelectric conversion film including a subphthalocyanine derivativerepresented by the following General Formula (1),

where, in General Formula (1),

X represents any substituent selected from among the group consisting ofa halogen, a hydroxy group, a thiol group, an amino group, a substitutedor unsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted alkyl amine group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted alkylthio group and asubstituted or unsubstituted arylthio group,

R₁ to R₃ each independently represent a substituted or unsubstitutedring structure, and

at least one of R₁ to R₃ includes at least one hetero atom in the ringstructure.

(10)

The solid-state image sensor according to (9),

wherein the photoelectric conversion film absorbs green light having awavelength of greater than or equal to 450 nm and equal to or less than600 nm and photoelectrically converts the absorbed green light.

(11)

The solid-state image sensor according to (9) or (10), configured as alaminated type solid-state image sensor, including:

a first chip in which the photoelectric conversion film is formed; and

a second chip in which a signal processing circuit configured to processa signal that is obtained by photoelectric conversion by thephotoelectric conversion film is formed, the second chip being laminatedwith the first chip.

(12)

An electronic device including:

a solid-state image sensor including a photoelectric conversion filmincluding a subphthalocyanine derivative represented by the followingGeneral Formula (1);

an optical system configured to guide incident light to the solid-stateimage sensor; and

an arithmetic processing circuit configured to perform arithmeticprocessing of an output signal from the solid-state image sensor,

where, in General Formula (1),

X represents any substituent selected from among the group consisting ofa halogen, a hydroxy group, a thiol group, an amino group, a substitutedor unsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted alkyl amine group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted alkylthio group and asubstituted or unsubstituted arylthio group,

R₁ to R₃ each independently represent a substituted or unsubstitutedring structure, and

at least one of R₁ to R₃ includes at least one hetero atom in the ringstructure.

REFERENCE SIGNS LIST

-   100 photoelectric conversion element-   102 substrate-   104 lower electrode-   106 p buffer layer-   108 photoelectric conversion layer-   110 n buffer layer-   112 upper electrode

1-12. (canceled)
 13. An imaging device, comprising: a photoelectricconversion film, comprising a subphthalocyanine derivative representedby the following General Formula (1),

where, in General Formula (1), X represents any substituent selectedfrom among the group consisting of a halogen, a hydroxy group, a thiolgroup, an amino group, a substituted or unsubstituted alkoxy group, asubstituted or unsubstituted aryloxy group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkyl aminegroup, a substituted or unsubstituted aryl amine group, a substituted orunsubstituted alkylthio group and a substituted or unsubstitutedarylthio group, R₁ to R₃ each independently represent a substituted orunsubstituted ring structure, and at least one of R₁ to R₃ includes atleast one hetero atom in the ring structure.
 14. The imaging deviceaccording to claim 13, wherein at least one of R₁ to R₃ has a ringstructure including a substituent.
 15. The imaging device according toclaim 14, wherein the substituent of R₁ to R₃ is a halogen.
 16. Theimaging device according to claim 13, wherein R₁ to R₃ have a ringstructure including a π-conjugated system structure.
 17. The imagingdevice according to claim 13, wherein R₁ to R₃ have a ring structureincluding 3 or more and 8 or fewer ring constituent atoms.
 18. Theimaging device according to claim 17, wherein R₁ to R₃ have a ringstructure including 6 ring constituent atoms.
 19. The imaging deviceaccording to claim 13, wherein a hetero atom included in the ringstructure of R₁ to R₃ is a nitrogen atom.
 20. The imaging deviceaccording to claim 13, wherein X is a halogen.
 21. The imaging deviceaccording to claim 13, wherein the photoelectric conversion film iscomposed of a bulk hetero mixed layer.
 22. The imaging device accordingto claim 13, wherein the subphthalocyanine derivative is a n-type lightelectric conversion material.
 23. A photoelectric conversion film,comprising: a subphthalocyanine derivative represented by the followingGeneral Formula (1),

where, in General Formula (1), X represents any substituent selectedfrom among the group consisting of a halogen, a hydroxy group, a thiolgroup, an amino group, a substituted or unsubstituted alkoxy group, asubstituted or unsubstituted aryloxy group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkyl aminegroup, a substituted or unsubstituted aryl amine group, a substituted orunsubstituted alkylthio group and a substituted or unsubstitutedarylthio group, R₁ to R₃ each independently represent a substituted orunsubstituted ring structure, and at least one of R₁ to R₃ includes atleast one hetero atom in the ring structure.
 24. The photoelectricconversion film according to claim 23, wherein at least one of R₁ to R₃has a ring structure including a substituent.
 25. The photoelectricconversion film according to claim 24, wherein the substituent of R₁ toR₃ is a halogen.
 26. The photoelectric conversion film according toclaim 23, wherein R₁ to R₃ have a ring structure including aπ-conjugated system structure.
 27. The photoelectric conversion filmaccording to claim 23, wherein R₁ to R₃ have a ring structure including3 or more and 8 or fewer ring constituent atoms.
 28. The photoelectricconversion film according to claim 27, wherein R₁ to R₃ have a ringstructure including 6 ring constituent atoms.
 29. The photoelectricconversion film according to claim 23, wherein a hetero atom included inthe ring structure of R₁ to R₃ is a nitrogen atom.
 30. The photoelectricconversion film according to claim 23, wherein X is a halogen.
 31. Thephotoelectric conversion film according to claim 23, wherein thephotoelectric conversion film composed of a bulk hetero mixed layer. 32.An electronic device, comprising: an imaging device, comprising: aphotoelectric conversion film, comprising a subphthalocyanine derivativerepresented by the following General Formula (1),

where, in General Formula (1), X represents any substituent selectedfrom among the group consisting of a halogen, a hydroxy group, a thiolgroup, an amino group, a substituted or unsubstituted alkoxy group, asubstituted or unsubstituted aryloxy group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkyl aminegroup, a substituted or unsubstituted aryl amine group, a substituted orunsubstituted alkylthio group and a substituted or unsubstitutedarylthio group, R₁ to R₃ each independently represent a substituted orunsubstituted ring structure, and at least one of R₁ to R₃ includes atleast one hetero atom in the ring structure; an optical systemconfigured to guide incident light to the imaging device; and anarithmetic processing circuit configured to perform arithmeticprocessing of an output signal from the imaging device.